Tone-mapping: Single RAW vs 7 exposures generated from single RAW

Had a few people inquiring after reading my blog post about HDR if I’d tried tone-mapping from a single RAW file. So here’s the result… the top image is tone-mapped from a single RAW file using Photomatix, the bottom image is tone-mapped from an HDR file generated from my 7 exposure from a single RAW method that I described in my blog post.

There are noticeable differences, the 7 exposure version definitely still gives a wider range of detail, it’s especially noticeable behind the pipe on the far right… I found it interesting that there was a slight color variation as well. I’ve uploaded this larger than I usually do to give you a better chance to see some of the differences.

Anyways… just thought I’d test it out and fill you all in!

Tags: hdr, jpg, photomatix, RAW, Tips, Tutorials

HDR : Battle Royale!

NOTE: Clicking on the images in this post will open them larger in a new window.

High Dynamic Range Imaging

HDR, or High Dynamic Range Imaging seems to be all the rage these days. HDRI is described as:

In image processing, computer graphics and photography, high dynamic range imaging (HDRI) is a set of techniques that allows a greater dynamic range of exposures (the range of values between light and dark areas) than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.

More accurately however, the images that are commonly seen and referred to as HDR or HDRI images are tone-mapped.

Tone mapping is a technique used in image processing and computer graphics to map a set of colours to another; often to approximate the appearance of high dynamic range images in media with a more limited dynamic range. Print-outs, CRT or LCD monitors, and projectors all have a limited dynamic range which is inadequate to reproduce the full range of light intensities present in natural scenes. Essentially, tone mapping addresses the problem of strong contrast reduction from the scene values (radiance) to the displayable range while preserving the image details and color appearance important to appreciate the original scene content.

Definitions and technicalities aside, I decided to look into HDR and tone mapping a bit closer to see if there really was a difference between different processes. I was curious to see if there was noticeable differences between generating HDR/tone-mapped shots from a single RAW, multiple RAWs, multiple JPGs from the camera, and multiple JPGs generated from a single RAW. For the purposes of the rest of this post, I will be referring to my final images as HDR images (even though we all now know that’s not exactly correct).

Here is the original, straight out of the camera image shot with my Canon Digital Rebel XT/350D.

Honestly, not a bad image for SOOC! Anyways, the recommended way to produce HDR is to take multiple exposures using your camera’s Auto Exposure Bracketting (AEB) setting. I’m not going to get into the details on this, I’m merely posting my comparison results here.

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Tags: bikers, bmw, car, comparison, hdr, hdri, hood, motorcycle, motorcycles, photomatix, photoshop, redynamix, reflection, test, tone mapped, tone mapping, tutorial